Top left: Hippocampus sp. internal structure
Top right: Short-snouted seahorse - Hippocampus hippocampus
Center: 1. Syngnathus hippocampus [now Hippocampus hippocampus]
2. Pegasus draconis [now Eurypegasus draconis] - the Little Dragonfish (*unrelated to Syngnathidae family*)
3. Syngnathus pelagicus - the Sargassum pipefish
Bottom: Phyllopteryx taeniolatus -the Weedy Sea Dragon

Despite their remarkable appearance, seahorses are true ray-finned bony fishes (class Actinopterygii, infraclass Teleostei), along with bass, mullets, eels, salmon, and lanternfish.

Many people know of the male seahorse incubating the eggs and giving “birth” to 100-1000 offspring after they hatch, but reproduction is similar throughout the order Syngnathidae (including the seahorses, leafy and weedy sea dragons, and pipefish). There’s a persistent myth that seahorses are monogamous, but that’s not strictly true. The majority of species are serially monogamous, and remain together throughout the mating season (until the male births the babies).

Another remarkable thing about seahorses (Hippocampus spp.) is that they’re the only fish with prehensile tails - even their close relatives, the sea dragons and pipefish, don’t have this adaptation. However, since the seahorses are the only ones that swim upright, and they have the poorest locomotive skills, they need to be able to anchor themselves to the sea flora in order to not be swept away. The Guinness Book of World Records has named Hippocampus zosterae, the dwarf seahorse, the slowest fish in the world, moving less than 5 ft [150 cm] an hour.

Aside from the seahorses, the razorfish (Aeoliscus strigatus) is the only other fish to swim “upright”.

Images:
Bulletin of the United States Fish Commission, Vol 1. 1881.
Arcana; or, The Museum of Natural History. George Perry, 1811.

Top: Bichir and trunkfish [top], Electric Catfish [bottom]
Center: Electric “eel” - Electrophorus electricus
Bottom: Indo-Pacific Moray Eel - Muraena nudivomer (now Gymnothorax nudivomer) 

A while ago I saw this Bird and Moon illustration of animals with misleading names, but I kept seeing people asking, “Ok, if they’re not THAT, then what ARE they?” For some reason, I completely forgot that I wanted to cover those questions, but hey, better late than never!

The electric eel isn’t an eel - it’s a knifefish. Knifefish (Gymnotiformes) are actually more closely related to electric catfish (Siluriformes) than they are to true eels (order Anguilliformes), but developed their electroconductive organs through convergent evolution - the first signs of the organ evolution in both the electric eel and the electric catfish appeared after they shared a common ancestor.

In addition to electric eels and electric catfish, electric rays (order Torpediniformes) are the only other “strongly electric” fishes - that is, fish that produce electric shocks over one volt, and use their electrogenerative organs to either stun or kill prey and/or attackers. There are many fish that can produce a small current (“weakly electric”), but it is used for electrolocation and electrocommunication, instead.

Images:
Fishes of Zanzibar: Acanthopterygii. J. Van Voorst, 1866.
The Standard Natural History. John Sterling Kingsley, 1884.
Wild life of the world. Richard Lydekker, 1915.

The Paenungulata

Despite their vast differences in their current appearance, the Sirenia, Hyracoidea, and Proboscidea are fairly closely related, in the grand scheme of things. The Paenungulata lived on the tidal shores of the Tethys Ocean. One line began to specialize in swimming and grazing on the shallow continental shelf, one began to specialize in browsing (eating from trees), and one began to specialize in grazing (eating grass and ground shrubs). Over time, these evolved into the three orders in the clade.

American Animals. Witmer Stone and William Everett Clam, 1905.
The Animal Kingdom. Hugh Craig, 1902.

One of these things is not like the other…

First row: Walrus (Odobenus rosmarus) skeleton
Second row: Hooded seal (Cystopkora cristata) skeleton
Third row: Dugong (Dugong dugon) skeleton, Brazilian sea lion (Otaria flavescens) skeleton.

*Skulls depicted are of species in the same genus as the skeleton.

Sirenia (manatees, dugongs, and sea cows) and Pinnipedia (the seals, walruses, and sea lions) are often seen as very similar, but they came from very different lineages.

While both came from land mammals (just like all sea mammals), the pinnipeds evolved from a bear-like ancestor, who returned to the sea around 28 MYA. They’re Caniformidae, or dog-like Carnivora.

The sirens evolved from the same ancestor as the hyraxes and elephants, and returned to the sea around 50 MYA. They’re only distantly related to Cetaceans and Pinnipeds.

Vergleicheende Osteologie. Edward D’alton, 1821.

Lysosquilla maculata - Mantis Shrimp

Lysosquilla maculata is just one of several species of very awesome mantis shrimp. I’ve loved these guys ever since I saw a video of one break an aquarium on board a research vessel, and it got washed back out to sea. Bad. Ass. They are fascinating creatures.

The Oatmeal totally knows what I’m talking about. Check out the comic.

Top Right Image: Dictionnaire Universel d’Histoire Naturelle. M. Charles d’Orbigny, 1849.
Bottom Image: Peacock Mantis Shrimp. Rick Collier Imagery, 2011.

biomedicalephemera:

Bottom: Short Beaked Echidna [right] (Tachyglossus aculeatus) and Western Long-Beaked Echidna [left] (Zaglossus bruijni)
Center Left: Starfish (Echinodermata spp.)
Center Right: Purple coneflower (Echinacea purpurea)
Top: Echidna (mythological)

Originally, “Echidna” was a Greek mythological figure, a monstrous snake-like creature, and the mother of Cerberus, the Chimera, the Gorgon, and more. Her name roughly translates to “she-snake”, and the monotreme known as the echidna is cited in many sources as being named after her.

However, it is becoming more accepted these days that the echidna has the same etymological origins as the Greek term “ekhinus”, or “sea-urchin/porcupine [spine-skinned]”. Though similar-sounding, “ekhidna” and “ekhinos” have distinct etymological histories, and should be recognized as different terms.

It’s unknown if “ekhinus” originally referred to the sea-urchin or the hedgehog/porcupine, but the use of the term in reference to Echinaceae (coneflowers) is a direct reference to the spiny nature of the sea-urchin.

pepperloves1:

“While the rarity and beauty of Harvard’s Glass Flowers have won them fame and made them the Harvard Museum of Natural History’s (HMNH) most popular exhibit, the glass animals exist in relative obscurity.”

The glass sea life of the Blaschkas is some of my favorite hand-blown art out there. I regret that I missed the opportunity to see it when it was at the Minnesota Science Museum back in 2006, but it’s still too cool to pass up.

underthevastblueseas:

Modern fishing vessels catch staggering amounts of unwanted fish and other marine life. It’s estimated that anywhere from 8 to 25 percent of the total global catch is discarded, cast overboard either dead or dying. That’s up to 27 million tonnes of fish thrown out each year — the equivalent of 600 fully-laden Titanics. And the victims aren’t just fish. Every year, an estimated 300,000 whales, dolphins and porpoises die entangled in fishing nets, along with thousands of critically-endangered sea turtles.

All modern forms of commercial fishing produce bycatch, but shrimp trawling is by far the most destructive: it is responsible for a third of the world’s bycatch, while producing only 2% of all seafood.

Shrimp (and many deep-sea fish) are caught using a fishing method called bottom trawling, which usually involves dragging a net between two trawl doors weighing several tons each across the ocean bed. This has a destructive impact on seabed communities, particularly on fragile deep water coral – a vital part of the marine ecosystem that scientists are just beginning to understand. The effect of bottom trawling on the seafloor has been compared to forest clear-cutting, and the damage it causes can be seen from space. The UN Secretary General reported in 2006 that 95 percent of damage to seamount ecosystems worldwide is caused by deep sea bottom trawling.

source

Relevant to my post on “Chilean Sea Bass”.

Patagonian Toothfish - Dissostichus eleginoides

Have you ever eaten “Chilean sea bass”? Just like sardines, they’re not actually a “real” fish species - they’re what’s been known for over a century as the Patagonian toothfish; in the UK and most other places in the world, they’re still called “toothfish”.

A man named Lee Lantz created the term “Chilean sea bass” in 1977, and the FDA approved it as an “alternative market name” in 1994. Since then, fisheries have been harvesting this predatory Antarctic fish en masse, and selling it like hotcakes to the restaurant and supermarket industries. The mild-but-fishy taste that’s stronger than your standard “whitefish” is easy to mix with other flavors, and the fish themselves can reach up to 20 lbs - big fish which are easy to sell by bulk weight.

Unfortunately, the regulation of fisheries that harvest the Patagonian toothfish is rather lacking. Unlike other fishery operations (such as the Caribbean swordfish industry), the companies that fish the Antarctic waters have largely not changed their practices in decades, despite recent calls to protect the endangered fish and mammals that are known to be killed by the practices used to over-harvest these profitable fish. That’s on top of depleting the natural populations of the fish to a point where they’re unable to repopulate their native seas, leading to a serious imbalance in the ecosystem.

If you have a choice in fish, trust me, “Chilean sea bass” isn’t the best out there. And until the fisheries operating in the Antarctic change their practices, you’re almost certainly helping to save the lives of endangered animals, and preserving what we already know to be an incredibly fragile ecosystem. Just a thought, next time you buy fish.

More on Marine Fisheries

Doris sumptuosa [now Hexabranchus sanguineus] - “Spanish Dancer”

The “Spanish Dancer” nudibranch is named for its flamboyant “skirts” that swish around like a flamenco dancer. Hexabranchus sanguineus is found around the world, wherever the water is warm enough.

The species was first described based on a specimen from the Red Sea, where its coloration is almost blood-red (hence the “sanguineus” - blood-like). However, the color can vary from red, to orange, to bright yellow (though pure yellow is quite rare).

These are some of the largest nudibranchs out there. Adults can reach up to 40 cm in length.

United States Exploring Expedition, under the command of Charles Wilkes: Atlas, Mollusca and Shells. Augustus A. Gould, 1856.

Artistic interpretations of sea life, birds, and reptiles

Between the beginning of the Scientific Revolution (which began in the mid-17th century) and the early-19th Century movement towards dry and clinical accuracy in both anatomical and zoological illustrations, there was a period of extravagance, showiness, and artistic expression in the sciences.

Instead of being solely geared towards other scientists, the artists sought to entice the general public and show off their vast collections, in many of their works. This can be seen in the medical illustrations of Frederick Ruysch, as well as here, in the zoological illustrations of Albertus Seba.

[h/t to Biodiversity Library’s blog for tipping me off to the interesting connections between two collections already in my archive]

Locupletissimi rerum naturalium thesauri accurata descripto, tome II & III. Albetus Seba, 1735.